1 files changed, 4 insertions, 0 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 29b70669435..34156260c9b 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1334,8 +1334,12 @@ asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *p
         error = -EINVAL;
         if (user_nd.mnt->mnt_root != user_nd.dentry)
                 goto out2; /* not a mountpoint */
+        if (user_nd.mnt->mnt_parent == user_nd.mnt)
+                goto out2; /* not attached */
         if (new_nd.mnt->mnt_root != new_nd.dentry)
                 goto out2; /* not a mountpoint */
+        if (new_nd.mnt->mnt_parent == new_nd.mnt)
+                goto out2; /* not attached */
         tmp = old_nd.mnt; /* make sure we can reach put_old from new_root */
         spin_lock(&vfsmount_lock);
         if (tmp != new_nd.mnt) {